System of operating devices in timed relation



Dec. 5, 1939. c. J. FITCH SYSTEM 0F OPERATING DEVICES IN TIMED RELATION Filed Oct. 20, 1936 ATTORNEY Patented Dec. @5, 1939 UNITED STATE ,@FFiCE SYSTEM F OPERATING DEVICES llN TD RELATION Application October 20, 1936, Serial No. 106,546

13 Claims.

This invention lrelates to synchronizing systems and more particularly to electronic synchronizing systems.

An object of the present invention is to provide a novel and more eflicient synchronizing system which comprises Wholly electrical means such as electronic discharge devices to maintain synchronization between remotely situated stations. l Other objects and features reside in the provision of means to generate the source of power at the remote stations and simultaneously to .transmit control signals initiated by the generated power to control the generation of the supply power at a diiferent remote station.

It will be obvious from the description herein that the present invention will have innumerable applications, in fact, it is applicable to practically all systems wherein apparatus, such as rotary equipment used in various forms of communication systems such as television, facsimile, printlng telegraph systems, etc., or electronic apparatus operating on a timed basis or utilizing a timed power supply which must be in exact phase relationship.

Various other objects and advantages of the invention will be obvious from the following particular description of one form of mechanism embodying the invention or from an inspection of the accompanying drawing; and the invention also constitutes certain new and useful features of construction and combination of parts hereinafter set forth and claimed.

In the drawing: Fig. 1 shows diagrammatically the circuit connections of a p referred form of the present synchronizing system,

Figs. 2 to 6 represent various characteristic curves of the wave forms of the system.

Referring now to Fig. l, a brief general description of the system will be given before describing in detail the preferred form of circuit connections. 'Ihe electron discharge devices ,I and 2 and associated circuits comprise a constant frequencyl oscillator system, so that upon closure of the control switch 3, the triode arrangement of tube I is activated to operate the normally high biased tube 2 permitting the tuned circuit 4 in the plate circuit thereof to be excited momentarily. The oscillations generated by the tuned circuit are in turn impressed upon amplifier 5 and filter 6 and the duplex diode arrangement of tube I. The rectifledvwaves are then impressed upon the triode of tube I so that a short control signal is impressed upon the electron discharge devices 2 and 1. The control sig- (ci. 17a-sas) nal activates the tube 2 to permit the tuned cir- 'cuitto be excited as just explained to energize tube I, thus establishing an oscillatory circuit arrangement capable of generating oscillations at a substantially constant frequency.

'I'he oscillation generator described is the subjectmatter of a copending application Serial No. 100,070, led Sept. 10, 1935.and may be referred to for a more complete description.

At the terminals 8 8, which are a source for constant frequency AC,` any' suitable equipment to be controlled may be connected and is generally designated at IQ. 'I'his apparatus, as it will be understood as the description progresses, may be of various types, such as rotary apparatus, electronic devices or other elements which are to bel controlled in a certain timed relationship with other similar apparatus remotely located. Upon closure of the switch 9 the control signals activating tube I at a certain definite frequency ai are then impressed upon the circuit I0 which may be any form of transmission media desired. The said signals activate the electron discharge devices II, I2 and i3 designated to be located at a remote station B so as to generate a constant frequency AC in the same manner as at the original station A to operate similar apparatus thereat and designated at M-a. The exact mode of operation thereof will now be set forth.

I'he electron discharge device I is shown comprising the combination of a full wave rectifier and triode in one envelope and is a type well knownin the art and commonly referred to as a duplex diode triode type. The diode plates I5 and I6 arejoined to the terminals of resistor I1, the center tap ofvwhich is connected to the grid I8 of the tube. A resistance I9 is inserted between the said center tap and the cathode of the tube. A condenser 20 is connected across the cathode and diode plate I 6, the purpose of which will be understood as the description progresses. The triode plate 2| is connected to positive battery by means of the control switch 3 and the negative sidethereof is extended to the cathode of the tube through resistor 22 and inductive Winding or coil 23. It is understood that normally the grid yI8 of the tube is at zero bias due to the fact that no currentis passing through resistor I 9, and therefore that upon closure of the control switch 3 current will ow through lthe tube I from the triode plate to cathode and through the resistance 22 and coil 23 to the negative side of the battery. 'I'he primaryA winding of transformer 24 'is connected in shuntwith the resistor 22 and the secondary winding thereof is included inq addition to the resistance 25 in the grid circuit of tube 2. A negative potential is shown normally applied to the said grid so that vthe tube is normally biased below cut-off. Associated with the plate of tuned circuit 4, the plate and cathode of tube 2 to the negative side of said source. The excitation of the tuned circuit at a frequency depending upon the LC constants of the circuit is impressed upon the coupling condenser 21 and the input to amplier 5. Between lthe tuned circuit and the input of the amplifier, phase shifting means is provided comprising the combination of condenser 21 and variable resistance 28. The phase shift may be eiected and varied slightly by means of adjusting the resistor 28 for nal adjustment, the purpose and application 'of which will be described later herein.

, The generated oscillations are amplified and passed through the lter 6 which is used merely for the purpose of Iiiltering out the higher harmonies and for delivering a pure sine wave at the output of the filter which in turn is impressed upon the terminals of resistor I1. It was mentioned hereinbefore that normally the grid I8 of tube I is at zero bias since there is no current passing through resistor I9. However, upon impression of the amplified oscillations at the terminals of the said arrangement the rectified waves passing through resistor I9 immediately drive the grid bias negative to prevent current ow in the triode plate circuit. Before the grid bias is eective to reduce the flow of plate current a short pulse is impressed upon the triode output circuit of tube I which includes the resistor 22 and coil 23. It was also mentioned that a condenser 20 is inserted between the cathode and one of the diode plates of the rectifier rof tube I. The curve in Fig. 3 shows the sinu soidal wave impressed across the diode plates of the tube. When the polarity is'such that current passes from one diode plate I5 to cat ode, this current .passes through resistor I9- charging the condenser 20 to the polarity as shown. At the end of this particular half cycle as the current passes through zero, the charge in the condenser maintains the grid of the tube negative with respect to the cathode of a value sufcient to permit no plate current to ow. The charge in the condenser leaks oi .through the resistor I9, and the values of the capacitance and resistance being such that the time constant of the circuit is adjusted to maintain the tube biased below cut-oi during the timed interval that the said half cycle of the A. C. wave passes through zero. The following half cycle passing from diode 'plate I6 to cathode and resistor I9 has reached suicient amplitude to maintain the tube biased below cut-ofi. At the end of the second half cycle the charge in condens'er 20 has completely leaked off, and so as the second half cycle passes through zero, the grid bias is zero and plate current again is permitted to flow through the tube-,impressing an impulse upon the output circuit of the triode including resistor 22 and coil 23. The curve in Fig. 4 shows the wave shape of the rectified voltcause a signal pulse to' ow from positive side of source 26 through the age across the resistor I9. The effect of condenser 20 is evident, suppressing the alternate peaks of the rectied wave as shown and as just explained the suppressed waves are reduced in amplitude so as to be ineffective to send out signals in the plate circuit whereas the unsuppressed waves are eiective to impress signals upon the output circuit and thus it is seen that but a single impulse is transmitted for a complete cycle of thev input oscillations. The impulses impressed upon resistor 22 then activate the input and output circuits of tube 2 as explaiiied to continue initiating the oscillations by virtue of the tuned circuit 4.. y This action is repeated and the explained circuits continue to oscillate, impulses being impressed upon the grid of tube 2 and the generated A. C. impressed upon the terminals of resistor I1 and an inverted rectied wave impressed upon the grid of tube I. The curve in Fig. 2 shows the wave shape across the said oscillatory circuit and Figs. 3 to 5 show the other wave shapes in other sections of the circuit as explained, Fig. 5 indicating the short pulses in the output circuit of tube I and impressed upon resistor 22 and coil 23.

The phase relationship of the waves generated by the oscillatory circuit,.the waves impressed upon the diode plates of tube I, and the impulses applied to the grid of tube 2 should be such that the impulses in the output circuit of tube I are impressed upon the grid of tube 2 during the peak or maximum amplitude of the sine wave generated in the tuned circuit. This relationship is clearly shown in the curves shown in Figs. 2 to 5 and can be effected by inserting, for example, condenser 29 in one side of the lteroutput circuit as shown. Since the impulses flowing through the plate circuit of tube I-occur at the zero point of the waves impressed thereupon, and since they must be impressed upon'the grid of the tube 2 at the peak of the generated wave in thel tuned circuit, it is obvious that the phase relationship between the terminals of resistor I1 and the tuned circuit must be degrees apart. This phase shift may be varied slightly by means of the adjustable resistor 28 for a nal adjustment. i

From the terminals 8-8 connected .to the output /of the ilter, a pure sine wave generated by the tuned circuit may be amplied and impressed upon any circuit connected thereto and adaptable for use with an oscillation or A. C. gnerator. The circuit may supply energy to familiar forms of rotary apparatus', or to electronic apparatus or other elements designed to be operated by the generated source and adapted to be operated in a timed relationship to similar apparatus or elements located remotely therefrom. The apparatus or elements are designated generally at I4 and I4a located at stations A and B, respectively.

The description thus far has been limited to the generation of the controlling energy' at the station A and the method for maintaining a source of a constant frequency supply.

'Ihe impulses shown in Fig. 5 which are impressed upon the output circuit of tube I -not only energize the resistor 22 for purposes of generating the A. C. energy at the Astation A as explained but also energize the coil 23 included in the grid circuit of tube 1. The said coil or winding may be considered as comprising inductance and capacitance, the distributed ca.-

pacity of the winding. which is indicated in agarose dotted unes at an, being su'mcient for the present operation. The said winding shunted by the distributed capacity as shown may be considered` as a tuned circuit generating sine waves when impulses lare impressed upon it and is tuned to a multiple of the frequency of the generated oscillations. However, the said circuit is highly damped by the resistor 3I'so that just one complete oscillation per impulse impressed thereupon is applied to the grid of tube l,\which in the present example is biased as indicated for operation near the center of its characteristic curve so tha-.t the wave is applied Without distortion and impressed upon the output transformer 32. Referring to Fig. 6, the curve shows the Wave shape developed by the circuit just described, the said waves, virtually a pure sine wave, are in exact phase relationship with the waves shown in Fig. 3 which are impressedv upon the diode plates of tube I.

Upon closure of switch 9 the signals impressed upon the output transformer and shown in Fig. 6 are impressed upon the transmitting medium represented at I0, the receiving transformer 33 at station B and the grid of tube II, which is normally biased ybelow cut-off so that no plate current can pass through the tube until a signal pulse is impressed thereupon to drive the tube to zero bias, but no farther due to the series grid resistor 34. The output circuit of tube II is energized and comprises the following circuit:`

from positive battery of source 35, plate, to cathode of tube H, plate to cathode of tube I2,

vresistor 36 to the negativeside of source 35. The

tube I2 is a duplex diode `triode type similar to the tube I at station A andas ,seen the diode plate connections and the grid circuit are the same as described in conjunction with tube I, so that it is evident that during the intervals that no signal is impressed upon the diode plates and resistor I9a the tube is at zero bias thereby permitting the circuit described throughthe tube to be completed. Energization of resistor 36 included in the output circuit of tube I2 vactivates the gridcircuit of tube I3 to energize the tuned circuit in the output circuit thereof to generate oscillations of a frequency equivalent to the frequency generated at station A. Thek generated oscillations are applied to an amplifier and filter as indicated and then to the diode plates of tube I2 exactly as explained hereinbefore. 'I'he oper, ation of tubes I 2 and I3 is similar to the operation of tubes I and 2, with the exception as just mentioned, namely, that the output circuit of tube i2 is controlled by the signal pulses energizing the tube II.

At the terminals 31-3'I, a circuit may be connected thereto, and upon which is impressed the/ generated AC energy which is then amplied and connected to the apparatus or elements designated I4--a which are operated in timed relationship with similar apparatus at station A and indicated at I4. y

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated andlin its operation may be made by those skilled in the art Without departing from the spirit of the invention.v Itis the intention therefore to be limited only as'k indicated by the scope of the following claims.

VWhat is claimed is as follows:

1. In a system for operating devices in timed relation comprising, in combination, means to generate oscillations at one station including meansto initiate periodically timed control signals, a device controlled by the oscillations at the said station, means Ato transmit the controlled signals, a second oscillation generating means,

means controlled by the controlled signals to control intermittently and periodically the operation of the second mentioned oscillation generating means, and a device controlled by the oscillation generated at the last mentioned station so that the two mentioned devices are operated in timed relationship.

2. The method of operating devices in timed relation which comprises generating oscillations of a predetermined frequency for a device at one station yand initiating periodic control signals bearing a definite-frequency relation with that of the generated oscillations and utilizing the signals to control intermittently and periodically the generation of oscillations at a second station for a device thereat, thereby operating the said devices in timed relationship.

-3. A system for operating devices in timed relationship comprising, in combination, means f to initiate periodically timed control signals at one station, means controlled by said signals to generate a constantly varying supply energy, a device controlled by the supply energy and means to transmit the control signals, means at a'second station controlled by the transmitted signals to generate a supply energy varying in timed relation with the first mentioned supply energy, and a device situated thereat and controlled by the supply energy generated so that the said devices are operated in a predetermined timed relationship.

4. A system of the character describedcomprising, in combination, lmeans to initiate periodically control signals, a circuit including oscillation generating means energized by the said control signals to produce oscillations of a predetermined frequency, means to impress the oscillations on said signal initiating means, and means to transmit the control signals, a second circuit including oscillation generating means excited periodically by the transmitted signals to gener- .ate oscillations of a frequency bearing a predetermined ratio tothe frequency of the control signals, and a device controlled by -the .oscillations generated by the last mentioned means.

5. A system of the character described comprising, in combination, a normallyfunexcited oscillation generating circuit, means to initiate periodically control signals to excite the said circuit thereby producing oscillations of a definite .frequency and a,devlce controlled by said oscillations, an additional normally unexcited oscillation generating circuit controlled by said control signals to produce oscillations the frequency of which is equal to that of the first mentioned oscillations and a second device controlled by the second mentioned oscillations produced so that the said devices are operated in a predetermined timed relationship.

6. A system of the character described comprising, in combination, means to initiate pericontrolled by the said control signals to produce oscillations the frequency of which is equal to that of the first mentioned oscillations, and a second device controlled by the second mentioned 5 oscillations produced so that the said devices are operated in a predetermined timed relationship.

'7. A system of the character described comprising, in combination, a normally unexcited oscillation generator, means to control the oper- 410 ation of the generator to produce oscillations of a predetermined frequency, a device controlled by said oscillations, and means to initiate periodically control signals, a second normally unexcited oscillation generator controlled by said 15 signals to produce, oscillations of a frequency bearing a predetermined relationship to that of the first mentioned oscillations, and a device controlled by the second mentioned oscillations so that the said devices are operated in a prede- 2@ termined timed relationship.

8. A sy'stem of the character described comprising, in combination, means to generate oscillations of a predetermined frequency including means to initiate periodically control signals, a 25 device controlled bysaid oscillations generated, a normally nexcited oscillation generating means, means controlled by the said signals to impress discrete excitation implses on said oscillation generating `means to produce oscillations the freg@ quency of which bears a predetermined relationship to that of the first mentioned oscillations, and a device controlled by the last mentioned oscillations so that the said devices are operated in a predetermined timed relationship.

9. A system of the character described comprising,

in combination, means comprising electron discharge means to generate oscillations of a predetermined frequency including means to initiate periodically control signals, a device controlled by said oscillations generated, a normally unexcited oscillation generating means, means comprising electron discharge means controlled by said signals to impress discrete excitation impulses on said oscillation Igenerating means the frequency of which j to produce oscillations,

bears a predetermined relationship to that of the I'lrst mentioned oscillations, and a device controlled by the last mentioned oscillations so that the said devices are operated in a predetermined relationship.

10. The method of generating supply energy for control purposes which comprises generating oscillations of a predetermined frequency for control purposes and periodic control impulses at one station, utilizing the control impulses to sustain further generation of the oscillations and to initiate control signals then transmitting the control signals to another station and utilizing the signals thereat to generate oscillations of the same said predetermined frequency so that the oscillations generated thereby for control purposes are in predetermined relationship with ther oscillations at the rst station. 11. A system of operating devices'in timed relation comprising normally unexcited oscillation generators at remotely situated stations and the oscillation generator atv one station being adapted to generate oscillations of a predetermined frequency for control purposes characterized by the fact that electron discharge means are provided for transmitting a series of discrete control signals and in timed relation with the generated oscillations to control the excitation of the oscillation generator at another station so that the oscillations generated thereby for control purposes are in vpredetermined timed relationship with the oscillations generated at the first station.

CLYDE J. FITCH. 

